1. Technical Field
The present invention relates to the display field, and more particularly to a gate output control method and a corresponding gate pulse modulator.
2. Description of the Related Art
Flat display (such as, liquid crystal display) has many advantages, such as high image quality, little size, light weight and wide application range, etc., thus it is widely applied into various consumption, such as mobile phone, notebook computer, desktop computer and television, etc. Therefore, the flat display has gradually substituted conventional cathode ray tube (CRT) display to be a main trend of the display.
Refer to FIG. 1, which is a schematic view of a conventional flat display. As shown in FIG. 1, the flat display 100 includes a substrate 110, a printed circuit board (PCB) 120 and a plurality of fixable circuit boards (FCB) 130. The substrate 110 has a plurality of gate drive integrated circuits (IC) GD1 and GD2, a plurality of source drive integrated circuits (not shown), and display blocks 111 and 112. The gate drive integrated circuits GD1 and GD2 are configured for controlling the display blocks 111 and 112 respectively and are coupled with each other in series through wire-on-array (WOA) technique. The printed circuit board 120 is electrically coupled to the substrate 110 through the flexible circuit boards 130, and has a timing controller 140 and a gate pulse modulator 150 disposed thereon. The timing controller 140 is configured for providing gate output enable signals YOE_Y1 and YOE_Y2 to the gate drive integrated circuits GD1 and GD2 respectively, and providing a gate control signal VGH1 and an oblique control signal to the gate pulse modulator 150 such that the gate pulse modulator 150 outputs a modulated gate control signal VGH to the gate drive integrated circuits GD1 and GD2. Then the modulated gate control signal VGH is cooperated with the gate output enable signals YOE_Y1 and YOE_Y2 to generate corresponding gate drive signals Gate Pulse_Y1 and Gate Pulse_Y2.
Refer to FIG. 2, which is a schematic view of a conventional gate pulse modulator. As shown in FIG. 2, the gate pulse modulator 150 is a pulse-width modulation integrated circuit, which includes a gate control signal terminal 151, an oblique control signal terminal 152, a discharge circuit 153 and an output terminal 154. The gate control signal terminal 151 is configured for receiving the gate control signal VGH1, the oblique control signal terminal 152 is configured for receiving the oblique control signal YV1C, and the gate pulse modulator 150 determines whether employing the discharge circuit 153 to discharge the gate control signal VGH1 for generating the modulated gate control signal VGH and employing the output terminal 154 to output the modulated gate control signal VGH to the gate drive integrated circuits GD1 and GD2 according to the oblique control signal YV1C.
Refer to FIG. 3, which is a timing chart of the gate control signal VGH1, the oblique control signal YV1C and the modulated gate control signal VGH of the gate pulse modulator as shown in FIG. 2, and the gate output enable signals YOE_Y1 and YOE_Y2, the gate drive signals Gate Pulse_Y1 and Gate Pulse_Y2 as shown in FIG. 1. As shown in FIG. 3, the modulated gate control signal VGH output from the gate pulse modulator 150 is a gate control signal with oblique, which falls to a certain voltage in a slope, and then changes in a vertical mode. In addition, since the resistance of the WOA is large, the modulated gate control signal VGH and the gate output enable signals YOE_Y1 and YOE_Y2 attenuate to generate wave-change in a process when they are transmitted to the gate drive integrated circuits GD1 and GD2, such that oblique cutoff voltages V1 and V2 of the gate drive signals Gate Pulse_Y1 and Gate Pulse_Y2 configured for driving the gate drive integrated circuits GD1 and GD2 have a voltage difference ΔV0 therebetween. Therefore, luminance of the display blocks 111 and 112 are different to generate a horizontal slight boundary. That is, the luminance is non-uniform in the perpendicular direction.